The non-mechanical types among us may not be as certain that "usually" turning the screw to the right, screws it in, and turning it left, screws it out. Also may not quite have the fact down that screwing the screw in leans the mixture and out, richens it. It's EZ to many of us but it boggles the mind of some of us.....I think there's plenty of room in gas modeldom for such an engine.....